The European Commission Open Source Observatory (OSOR) has published the updated OSOR Handbook, a practical guide for European public administrations seeking to use, develop, or contribute to open source software.
The handbook covers the full cycle of working with open source in the public sector. It explains how to find and evaluate existing open source solutions, including through software catalogues maintained by governments and other organisations. For cases where no suitable software exists, it addresses internal development and procurement of development services. The guide also covers participation in open source communities, funding models, the legal framework including licensing, and organisational structures such as Open Source Programme Offices (OSPOs). A final chapter points to further resources and networking opportunities.
The handbook builds upon on the draft 2024 draft, which was drawn up based on workshops and webinars with experts from public administrations across EU Member States, and complemented by OSOR's research and resources from the open source community. It consolidates the practical experience from almost two decades of OSOR's work supporting public administrations in adopting open source software.
This revised edition incorporates feedback on the 2024 draft gathered through a community written consultation, a subsequent workshop in with experts from European public administrations and discussions at FOSDEM 2025. Key additions include coverage of municipal-level open source catalogues, the EU Open Source Solutions Catalogue, expanded funding examples from several Member States, and references to recent EU legislation such as the Cyber Resilience Act and AI Act.
The OSOR Handbook is available for download from the OSOR Knowledge Centre.
